Title :
Performance Analysis of an Angle Differential-QAM Scheme for Resolving Phase Ambiguity
Author :
Hwang, Jeng-Kuang ; Chiu, Yu-Lun
Author_Institution :
Commun. Signal Process. Lab. Inst. of Commun. Eng., Yuan-Ze Univ., Taipei
Abstract :
An angle differential-QAM (ADQAM) scheme is proposed to solve phase ambiguity problem in non-data-aided continuous transmission system with square QAM constellation. Starting from the 16-ADQAM case, we derive differential encoding and decoding schemes in terms of two differential angles, and use a solar system analogy for explanation. The 16-ADQAM system incurs only about 0.5-dB performance degradation as compared to the coherent 16-QAM system under AWGN channel. Generalization to flat fading channel and higher-level ADQAM are straightforward. For educational purpose, a demonstrative 16-ADQAM system is realized in terms of an audio-band software-defined-radio approach, and experimental result shows the feasibility of real-time speech transmission.
Keywords :
Rayleigh channels; quadrature amplitude modulation; software radio; Rayleigh fading; angle differential-QAM scheme; audio-band software-defined-radio; flat fading channel; performance analysis; phase ambiguity; AWGN channels; Constellation diagram; Decoding; Degradation; Fading; Performance analysis; Quadrature amplitude modulation; Quadrature phase shift keying; Solar system; Speech; Differential coding scheme; Rayleigh fading; continuous transmission system; performance analysis; phase ambiguity; square QAM;
Conference_Titel :
Advanced Communication Technology, 2008. ICACT 2008. 10th International Conference on
Conference_Location :
Gangwon-Do
Print_ISBN :
978-89-5519-136-3
DOI :
10.1109/ICACT.2008.4493734
